Reforming of both straight run and cracked gasolines to provide high octane fuels



Aprll 3, 1956 v. HAENSEL. ETAL 2,740,751

REFORMING OF BOTH STRAIGHT RUN AND CRACKED GASOLINES TO PROVIDEHIGH OCTANE FUELS Filed Feb. 25, 1952 .u oONN lam:

thermally cracked stream or other olefinic stream having a large quantity of unsaturated material. Preferably, each of the streams are depentanized and boiling within the range of from about 115 F. to about 400 F., as indicated. l

The straight run fraction in column 3 is distilled and fractionated to provide an overhead cut, boiling in the range of from about 115 F. to about 220 F., and being withdrawn by way of line 7 and valve 8, while a bottoms fraction passes by wayvof line 9 and valve 10 into a second fractionation column 11 to be further distilled and separated into an intermediate boiling point fraction and a higher boiling fraction. The intermediate boiling point fraction is indicated as boiling in the range of from about 220 F. to 270 F. and discharged by way of line 12 and valve 13, while the higher boiling fraction is indicated as ,boiling in the range of from about 270 F. to about 400 Ft being withdrawn by way of line 14 and valve 15.

The olenic cracked gasoline fraction is separated in column 6 to provide an overhead stream, boiling in the range of from about 115 F. to about 220 F., andbeing discharged by way of line 16 and valve 17, while a bottoms fraction is passed by way of line 18 and valve 19 into a second fractionating column 20 for further distillation and separation. An intermediate boiling point fraction having a boiling range of from about 220 F. to about 300 F. is dischargedfrom the upper portion of column 20 by way of line 21 and valve 22, while the heavier fraction, having a boiling point range of from about 300. F. to about 400 F., is withdrawn from the lower end of column 20 by way of line 23 and valve 24.

In accordance with the present combined and integrated operation, the low boiling straight-run fraction from line 7 iscombined with the intermediate boiling point cracked fraction from line 21, as well as with recycle hydrogen obtained from line 25, and the mixture is then heated in a suitable heater or furnace 26 and discharged by way of line 27 to a catalytic reforming zone indicated diagrammatcally at 28. The low boiling and intermediate boiling point cuts which are combined and passed to this reforming zone provide naphthenic hydrocarbons suitable for dehydrogenation and aromatization and the production of a considerable quantity of benzene, toluene, and xylenes suitable for high octane blending components. Thus, in orderto effect substantial dehydrogenation of the stream, the material passing by way of line 27 into the reforming zone 28 is at a temperature say of about 900 F. or within the range of from about 800 F. to 950 F., while at a pressure of preferably less than about 400 p. s. i. g., and preferably within the range of from about 200400 p. s. i. g.

Preferably, the catalyst used in the reforming zone 28 is of the improved type comprising platinum-alumina and combined halogen, in order to provide superior results and in order to provide -a substantially non-regenerative type of operation. It is, however, to be understood, that more than one reforming zone or chamber may be utilized with suitable heaters or heat exchange means placed between the separate catalytic contacting chambers of the unit. The reformed stream from zone 28 is passed by way of line 29 and valve 30 to a suitable cooler 31, and froml the latter by way of line 32 into a separator 33. From theseparator 33, a liquid aromatic containing hydrocarbon stream is withdrawn by way of line 34 and valve 35, while a gaseous hydrogen containing streamis discharged from the upper portion thereof by way of line 36 and valve 37. Means is also provided by way of line 38 and valve 39 for withdrawing a portion of the gaseous stream and thus preventing the build-up of methane or other undesired light gaseous components.

The intermediate boiling point range straight-run cut from column 11,"and passing by way of line 12, is combined with a hydrogen stream from line 40 and compresser 41 and the mixture is passed by way of a suitable heater 42 and line 43 into a separate reforming zone indicated as 44. This naphthenic fraction, containing some virgin toluene and xylene along with toluene and Xylene forming naphthenes, undergoes reforming and aromatization within the reforming unit 44 at a temperature of the order of about 900 F., or with in the range of from about 800 F. to about 950 F., While at a pressure of preferably less than about 500 p. s. i. g., and within the range of from about 250 to 500 p. s. i. g. As noted in connection with catalytic reforming zone 28, the present reforming zone 44 may comprise one or more separate catalytic chambers having suitable heaters or heating means incorporated therebetween so as to provide suitable reforming conditions and maximum conversion to high octane fractions. Also, an improved platinumalumina-combined halogen catalyst is preferably used in the reforming zone 44.

The resulting reformed fraction from zone 44 passes by way of line 45 and valve 46 to a cooler 47 and from the latter by way of line 48 into a separator 49. From the latter a liquid hydrocarbon stream of high toluene and xylene concentrations is passed by way of line 50 and valve 51, while a gaseous hydrogen-containing stream is discharged from the upper portion of the chamber by way of line 25 and valve 52. In accordance with a particular feature of the present operation, it is to be noted that this hydrogen containing gaseous stream being discharged from separator 49 by way of line 2d is that which is combined with the light straight-run cut and the intermediate boiling point cracked gasoline cut and passing to reforming zone 28. The operating pressures are controlled so that there is no compressor required in line 25 to maintain the hydrogen recycle stream. In other words, reforming zone 23 operates at a lower pressure than reforming zone 44 and the compressor 41 provides a high pressure for the hydrogen stream leaving the separator 33 suitable to maintain pressure through reforming zone 44, through the cooler 47 and the separator 49 and thus permit the recycle of the hydrogen stream, by way of line 25, back into the iirst catalytic reforming zone 28.

In accordance with a. further portion of the present combined operation, the high boiling straight-run cut, being withdrawn by Way of line 14 from column 11, passes in admixture with hydrogen obtained from line 54 through heater 53 and charge line 55 to a third catalytic reforming zone 56. ln zone 56, the high boiling cut is subjected to more severe reforming conditions, say at a temperature of about 900 F. or within the range of from about 800 F. to about 950 F., and a pressure above 500 p. s. i. g., say at about 700 p. s. i. g., or within the range of from about 500 to 800 p. s. i. g. As in the other separate reforming zones, the present high boiling cut contacts preferably la platinumalumina-combined halogen catalyst suitable to provide overall reforming including dehydrogenation and isomerization and hydrocracking, with resulting optimum conversions to high octane materials in a manner where each zone is substantially non-regenerative. In this instance, the resulting reformed stream from zone 56 passes Without additional heat directly to a catalytic hydrogenation zone 57, by way of line 58, while in admixture with the low boiling cut of cracked gasoline being discharged byway of line 16 and passing by way of a suitable heater or exchanger 59 and line 60. In other words, the olelinic cracked gasoline fraction from the fractionator 6 is combined with the reformed stream obtained from the high boiling cut of the straight-run charge stream and the mixture is subjected to catalytic hydrogenation in the zone 57 whereby to effect the saturation of the olenic components in the stream.

The resulting reformed and saturated product stream from the hydrogenation zone 57 passes by way of line 61 to cooler 62 and through line 63 into a suitable separating chamber 64. From separator 64, a gaseous hydrogen-containing stream is discharged by way of liucv 65 is diagrammatic only. Nor is the specific operation with respect to boiling points of particular cuts or fractions to be considered limiting, for lobviously, minor variations in carrying out the fractionation to obtain'the various low, intermediate, and high boiling point cuts may be made in accordance with the present combined and integrated operation to provide both motor fuel and aviation fuel of high octane. No pumps have been shown in the drawing, however, necessary pumps, and additional valves, as well as reboilers and the like, are of course to be incorporated in all units as may be required.

We claim as our invention:

l. An integrated and combined process for reforming both straight-run and cracked gasoline fractions to provide high octane number fuels, which comprises, fractionating each of the straight-run and cracked gasoline fractions to provide low, intermediate, and high boiling fractions, combining the low boiling straight-run fraction with the intermediate boiling cracked fraction and subjecting the mixture to reforming in the presence of a reforming catalyst within a rst reforming zone, subjecting the resulting intermediate straight-run fraction to reforming in a secondvcataiytic reforming zone, subjecting the resulting high boiling straight-run fraction to reforming in a third reforming zone and passing the resulting stream with hydrogen and without additional heating into a hydrogenation zone in admixture with the low boiling cracked gasoline fraction, contacting said mixture with a sulfur resistant hydrogenation catalyst in said hydrogenation zone in a manner effecting the saturation of oleiinic components of said stream, independently separating and fractionating the resulting reformed streams from each of said first and second reforming zones and from said hydrogenation zone in a manner providing high and low boiling fractions, blending the untreated high boiling cracked fraction with the resulting low boiling fractions from said rst and second reforming steps and with the high boiling fraction from said hydrogenation step to provide a desirable premium motor fuel, and blending the low boiling fraction from said hydrogenation step with both the resulting high boiling fractions separated from said first and second reforming zones to provide a premium aviation fuel.

2. An integrated and combined process for reforming straighbrun and cracked gasoline fractions to provide high octane number fuels, which comprises, separately fractionating the straight-run and cracked gasoline fractions to provide low boiling, intermediate boiling, and high boiling fractions, combining the resulting low boiling straight-run fraction with the intermediate boiling cracked fraction and subjecting the mixture to reforming in the presence of hydrogen and a platinum-aluminacombined halogen catalyst in a first reforming Zone, separating a gaseous hydrogen-containing stream from the resultant reformed products, subjecting the intermediate straight run fraction to reforming in the presence of said hydrogen stream separated from rst said reforming zone and while in contact with a platinumalumina-com bined halogen catalyst in a second reforming zone, cooling and separating the resulting reformed stream to pro-- vide a gaseous hydrogen containing stream and a liquid aromatic containing hydrocarbon stream, subjecting the high boiling straight-run fraction to reforming in the presence of a recycle hydrogen stream and in contact with a platinum-alumina-combined halogen catalyst in a third reforming zone, passing the resulting stream from said third reforming zone and without adidtional heating into a hydrogenation zone in admixture with the low boiling cracked gasoline fraction, said mixture contracting a sulfur resistance platinum-alumina catalyst in said hydrogenation zone and effecting the saturation of olefinic components of said stream, cooling and separating the resulting reformed and saturated stream to provide a gaseous hydrogen containing stream and a liquid hydrocarbon stream, with said hydrogen containing stream beingrecycled into admixture with said high boiling straight-run fraction as said hydrogen recycle stream, and further recycling at least a portion of said gaseous hy-` drogen containing stream being separated from said sec# ond reforming zone into admixture with said low boiling straight run-fraction and said intermediate boiling cracked fraction to provide the aforesaid hydrogen passing to said first reforming zone, independently separating and fractionating the resulting reformed streams from each of said first and second reforming zones and from said hydrogenation zone in a manner providing high and low boiling fractions, blending the untreated high boiling cracked fraction with the resulting low boiling reformed fractions from said first and second reforming zones and with the low boiling reformed fraction from said hydrogenation step whereby to provide a desirable premium motor fuel, and blending the low boiling fraction from said hydrogenation step with both of the resulting high boiing reformed fractions separated from said rst and second reforming zones whereby to provide a premium aviation fuel.

3. The method of claim 2 further characterized in that said straight-run and cracked gasoline fractions are depentanized prior to fractionation into said low, intermediate and high boiling fractions, and the resulting reformed streams from each of said separate reforming zones 'are depentanized prior to providing said low and high boiling reformed fractions being blended into said motor and aviation fuels.

4. An integrated and combined process for reforming straight-run and cracked gasoline fractions to provide high octane fuels, which comprises, separately fractionating the straight-run and cracked gasoline fractions to provide low boiling, intermediate boiling, and high boiling fractions of each, combining the resulting low boiling straghtmn fracton with the intermediate cracked fraction and subjecting the mixture to reforming at a temperature of the order of about 900 I". and a pressure of less than about 400 p. s. i. g. while in the presence of hydrogen obtained as hereinafter set forth and while in contact with a platinum-alumina-combined halogen catalyst in a first reforming zone, separating the resulting reformed stream into a gaseous hydrogen containing stream and a liquid aromatic containing stream, subjecting the intermediate straight-run fraction to reforming in the presence of said hydrogen stream separated from rst said reforming zone at a temperature of the order of about 900 F. and a pressure of less than about 500 p. s. i. g. but greater than the pressure maintained in first said reforming zone and while in contact with a platinurn-alumina-combined halogen catalyst within a second reforming zone, cooling and separating the resulting reformed stream to provide a gaseous hydrogen containing stream and a liquid stream containing aromatic hydrocarbons, subjecting the high boil-I ing straight-run fraction to reforming in the presence of a recycle hydrogen stream at a temperature of the order of 900 F. and a pressure greater than about 500 p. s. i. g. while in contact with a platinum-alumina-catalyst tained in a third reforming zone, passing the resulting stream from last said reforming zone and without additional heating into a hydrogenation zone in admixture with the low boiling cracked gasoline fraction, said mixture contacting a platinum-alumina catalyst at a temperature of the order of about 700 F. and a pressure greater than about 500 p. s. i. g. within said hydrogenation zone, effecting the saturation of oleinic components of said combined stream in said zone, cooling and separating the resulting reformed and saturated stream to provide a gaseous hydrogen containing stream and a liquid hydrocarbon stream, said k,hydrogen containing stream being recycled at least in part into adrnixture with said high boiling straight-run fraction as said hydrogen recycle stream, and further recycling at least a portion of said gaseous hydrogen containing stream being separated from said second reforming zone into admixture with said low boil ing straight-run fraction and said intermediate boiling cracked fraction to provide the aforesaid hydrogen passing to said first reforming zone, independently separating and fractionating the resulting reformed streams from each of said first and second reforming zones and from said hydrogenation zone in a manner providing depentanized high and low boiling fractions, blending the untreated high boiling cracked fraction with the resulting low boiling reformed fractions from said first and second reforming zones and with the high boiling reformed fractions from said hydrogenation step whereby to provide a desirable premium motor fuel, and blending the low boiling fraction from said hydrogenation step with both of the resulting high boiling reformed fractions separated from said first and second reforming zones whereby to provide a premium aviation fuel.

5. The method of claim 4 further characterized in that the hydrogen containing gaseous stream separated from said first reforming zone is compressed and raised to an elevated pressure of less than about 500 p. s. i. g. and sufficient to pass into said second reforming zone, and the resulting hydrogen containing gaseous stream separated from said reformed stream from second reforming zone is subsequently passed without an increase to pressure into first said reforming zone at a pressure less than that maintained in second reforming zone.

6. The method of claim 4 further characterized in that said straight-run gasoline fraction is fractionated to provide a low boiling cut boiling within the range of from about 115 F. to about 220 F., an intermediate cut boiling in the range of from about 220 F. to about 270 F., and a high boiling cut having a boiling range of from about 270 F. to about 400 F., and said cracked gasoline fraction is fractionatedto provide a low boiling cut having a boiling point range of from about 115 F., to about 220 F., an intermediate cut boiling in the range of from about 220 F. to about 300 F., and a high boiling cut having a boiling range of from about 300 F. to about 400 F.

7. The method of claim 4 further characterized in that each of said reforming streams from said separate reforming zones are fractionated to remove pentanes and higher materials prior to separating said streams into low and high boiling reformed fractions, and said pentanes and lighter materials are subsequently fractionated to provide an isopentane stream, and at least a portion of said isopentane is blended with said low boiling fraction from said hydrogenation step and the high boiling reformed fractions from said first and second reforming zones to provide said premium aviation fuel.

8. A process for producing high octane number fuels which comprises separately fractionating a straight-run gasoline and a cracked gasoline and separating from each of the gasolines a light, an intermediate and a heavy fraction, combining the light straight-run fraction with the intermediate cracked fraction and reforming the mixture in a first zone, separately reforming the intermediate straight-run fraction in a second zone, reforming the heavy straight-run fraction in a third zone, introducing the reformed products from the third zone, the light fraction of said cracked gasoline and hydrogen into a hydrogenation zone and therein saturating oleins with hydrogen, independently fractionating the products from each of said first and second zones and said hydrogenation zone and separating from each of the product streams a light fraction and a heavy fraction, blending the untreated heavy fraction of said cracked gasoline with the light product fractions from said rst and second zones and with the heavy product fraction from said hydrogenation zone to form a motor fuel, and blending the light product fraction from said hydrogenation zone with the heavy product fractions from said first and second zones to form an aviation fuel.

9. The process of claim 8 further characterized in that each of the reforming steps is effected in the presence of hydrogen, with hydrogen being passed from the rst to the second zone and being recycled from the second to the first zone, and still further characterized in that a hydrogen-containing gas is separated from the products of said hydrogenation zone and at least a portion thereof supplied to said third zone.

10. The process of claim 1 further characterized in that the reforming in each of said first, second and third zones is effected in the presence of hydrogen and platinumcontaining catalyst.

1l. The process of claim 1 further characterized in that the reforming in each of said first, second and third zones is effected in the presence of hydrogen and platinumalumina-combined halogen catalyst.

12. The process of claim 8 further characterized in that the reforming in each of said rst, second and third zones is effected in the presence of hydrogen and platinumcontaining catalyst.

13. The process of claim 8 further characterized in that the reforming in each of said first, second and third zones is effected in the presence of hydrogen and platinumalumina-combined halogen catalyst.

References Cited inthe le of this patent UNITED STATES PATENTS 2,304,183 Laying et al. Dec. 8, 1942 2,304,187 Marscher Dec. 8, 1942 2,415,998 Foster Feb. 18, 1947 2,423,328 Laying July 1, 1947 2,478,916 Haensel Aug. 16, 1949 OTHER REFERENCES World Petroleum, received February 6, 1951. Re-

print in Div. 31; pp. 315-34.

Kastens et al.: Ind. and Eng. Chem, vol. 42, No. 4, pp. 582-593, especially 587 and 593. 

1. AN INTEGRATED AND COMBINED PROCESS FOR REFORMING BOTH STRAIGHT-RUN AND CRACKED GASOLINE FRACTIONS TO PROVIDE HIGH OCTANE NUMBER FUELS, WHICH COMPRISES, FRACTIONATING EACH OF THE STRAIGHT-RUN AND CRACKED GASOLINE FRACTIONS TO PROVIDE LOW, INTERMEDIATE, AND HIGH BOILING FRACTIONS, COMBINING THE LOW BOILING STRAIGHT-RUN FRACTION WITH THE INTERMEDIATE BOILING CRACKED FRACTION AND SUBJECTING THE MIXTURE TO REFORMING IN THE PRESENCE OF A REFORMING CATALYST WITHIN A FIRST REFORMING ZONE, SUBJECTING THE RESULTING INTERMEDIATE STRAIGHT-RUN FRACTION TO REFORMING IN A SECOND CATALYTIC REFORMING ZONE, SUBJECTING THE RESULTING HIGH BOILING STRAIGHT-RUN FRACTION TO REFORMING IN A THIRD REFORMING ZONE AND PASSING THE RESULTING STREAM WITH HYDROGEN AND WITHOUT ADDITIONAL HEATING INTO A HYDROGENATION ZONE IN ADMIXTURE WITH THE LOW BOILING CRACKED GASOLINE FRACTON, CONTACTING SAID MIXTURE WITH A SULFUR RESISTANT HYDROGENATION CATALYST IN SAID HYDROGENATION ZONE IN A MANNER EFFECTING THE SATURATION OF OLEFINIC COMPONENTS OF SAID STREAM, INDEPENDENTLY SEPARATING AND FRACTIONATING THE RESULTING REFORMED STREAMS FROM EACH OF SAID FIRST AND SECOND REFORMING ZONES AND FROM SAID HYDROGENATION ZONE IN A MANNER PROVIDING HIGH AND LOW BOILING FRACTIONS, BLENDING THE UNTREATED HIGH BOILING CRACKED FRACTION WITH THE RESULTING LOW BOILING FRACTIONS FROM SAID FIRST AND SECOND REFORMING STEPS AND WITH THE HIGH BOILING FRACTION FROM SAID HYDROGENATION STEP TO PROVIDE A DESIRABLE PREMIUM MOTOR FUEL, AND BLENDING THE LOW BOILING FRACTION FROM SAID HYDROGENATION STEP WITH BOTH THE RESULTING HIGH BOILING FRACTION SEPARATED FROM SAID FIRST AND SECOND REFROMING ZONES TO PROVIDE A PREMIUM AVIATION FUEL. 